Dauchert, in U.S. Pat. No. 3,067,458, discloses an apparatus and process for melt spinning polymeric filaments and quenching the filaments by continuously directing a constant velocity current of cooling gas radially inward from all directions towards the filaments through a foraminous distribution cylinder surrounding the filaments and thence concurrently downward with the filaments. These radical quench systems provide "constant" amounts of radial flow through the distribution cylinder from its top (near the spinneret) to its bottom (at the exit from the quench chamber).
Broaddus et al, in U.S. Pat. No. 4,712,988, discloses an apparatus for radially quenching melt spun filaments with a similar foraminous distribution cylinder located in a quench chamber between the filaments and a gas supply chamber, but Broaddus provides areas of progressively decreasing porosity from a location immediately below the spinneret toward the exit from the quench chamber. Thus Broaddus' vertical gas distribution pattern through the foraminous distribution cylinder was defined by maximum gas flow immediately below the spinneret decreasing to a minimum gas flow at the exit from the quench chamber. This pattern is referred to herein as "gradient", and has achieved dramatic improvements in spinning performance at higher spinning productivities, as disclosed by Broaddus et al.
However, when it has been desired to spin filaments of lower denier per filament at high spinning densities as disclosed herein, neither the "constant" pattern of Dauchert nor the "gradient" pattern of Broaddus have given satisfactory results.